Preoperative localization of lesions of the parathyroid gland using thallium-technetium scintiscanning

Double tracer scanning of the neck after injection of thallium-210 and technetium pertechnetate was performed upon 33 patients with biochemically proved hyperparathyroidism operated upon during the past 14 months. Operative findings were correlated with the scans. Twenty-two of 29 single lesions of the parathyroid gland were successfully localized. There were ten unsuccessful studies, including three instances in which diffuse hyperplasia was incompletely identified. In one instance of diffuse hyperplasia, the bilateral pathologic finding was diagnosed correctly. Two of three substernal lesions were demonstrated in patients who had undergone previous unsuccessful explorations. An additional substernal lesion was localized in a patient prior to initial exploration. Nineteen of 21 lesions weighing more than 300 milligrams were identified, whereas only 50 per cent of the lesions weighing less than 300 milligrams could be seen. The scans demonstrated 12 of 14 lesions with C-terminal parathyroid hormone levels of more than 900 picograms per milliliter but only 60 per cent of the lesions that produced levels of less than 900 picograms per milliliter. Thallium-technetium scanning is a useful procedure for preoperative localization of parathyroid lesions and may preclude the need for more invasive testing in previously operated upon patients.